<div class="navigation">
            <input type="checkbox" class="navigation__checkbox" id="navi-toggle">

            <label for="navi-toggle" class="navigation__button">
                <span class="navigation__icon">&nbsp;</span>
            </label>

            <div class="navigation__background">&nbsp;</div>

            <nav class="navigation__nav">
                <ul class="navigation__list">
                    <li class="navigation__item"><a href="#" class="navigation__link"><span>01</span>About Us</a></li>
                    <li class="navigation__item"><a href="#" class="navigation__link"><span>02</span>Your benfits</a></li>
                    <li class="navigation__item"><a href="#" class="navigation__link"><span>03</span>Popular tours</a></li>
                    <li class="navigation__item"><a href="#" class="navigation__link"><span>04</span>Stories</a></li>
                    <li class="navigation__item"><a href="#" class="navigation__link"><span>05</span>Book now</a></li>
                    </ul>
            </nav>
        </div>

$color-white: #fff;
$color-black: #000;
$color-primary: #90CAF9;
$color-primary-light: #03A9F4;
$color-primary-dark: #03A9F4;
$color-grey-dark-2: #E0E0E0;
$color-grey-dark-3: #B0BEC5;


@import url(https://fonts.googleapis.com/css?family=Open+Sans:400,700);

*,
*::after,
*::before {
    margin: 0;
    padding: 0;
    box-sizing: inherit;
}

html {
  height: 100%;
}

body {
  background: $color-grey-dark-2;
    font-family: 'Open Sans', sans-serif;
    font-weight: 400;
    font-size: 18px;
    line-height: 24px;
    color: $color-black;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  display: flex;
  height: 100%;
  align-items: center;
  justify-content: center;
}

.navigation {
    &__checkbox {
        display: none;
    }

    &__button {
        background-color: $color-white;
        height: 7rem;
        width: 7rem;
        position: fixed;
        top: 6rem;
        right: 6rem;
        border-radius: 50%;
        z-index: 2000;
        box-shadow: 0 1rem 3rem rgba($color-black, .1);
        text-align: center;
        cursor: pointer;

    }

    &__background {
        height: 6rem;
        width: 6rem;
        border-radius: 50%;
        position: fixed;
        top: 6.5rem;
        right: 6.5rem;
        background-image: radial-gradient($color-primary-light, $color-primary-dark);
        z-index: 1000;
        transition: transform .8s cubic-bezier(0.86, 0, 0.07, 1);

    }

    &__nav {
        height: 100vh;
        position: fixed;
        top: 0;
        left: 0;
        z-index: 1500;
        visibility: hidden;
        opacity: 0;
        width: 0;
        transition: all .8s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    }

    &__list {
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%,-50%);
        list-style: none;
        text-align: center;
        width: 100%;
    }

    &__item {
        margin: 1rem;
    }

    &__link {
        &:link,
        &:visited {
            display: inline-block;
            font-size: 3rem;
            font-weight: 300;
            padding: 1rem 2rem;
            color: $color-white;
            text-decoration: none;
            text-transform: uppercase;
            background-image: linear-gradient(120deg, transparent 0%, transparent 50%, $color-white 50%);
            background-size: 220%;
            transition: all .4s;

            span {
                margin-right: 1.5rem;
                display: inline-block;
            }
        }
        
        &:hover,
        &:active {
            background-position: 100%;
            color: $color-primary;
            transform: translateX(1rem);
        }
    }


    //FUNCTIONALITY
    &__checkbox:checked ~ &__background {
        transform: scale(80);
    }

    &__checkbox:checked ~ &__nav {
        opacity: 1;
        width: 100%;
        visibility: visible
    }


    //ICON
    &__icon {
        position: relative;
        margin-top: 3.5rem;

        &,
        &::before,
        &::after {
            width: 3rem;
            height: 2px;
            background-color: $color-grey-dark-3;
            display: inline-block;
        }

        &::before,
        &::after {
            content: "";
            position: absolute;
            left: 0;
            transition: all .2s;
        }

        &::before { top: -.8rem; }
        &::after { top: .8rem; }
    }

    &__button:hover &__icon::before {
        top: -1rem;
    }

    &__button:hover &__icon::after {
        top: 1rem;
    }

    &__checkbox:checked + &__button &__icon {
        background-color: transparent;
    }

    &__checkbox:checked + &__button &__icon::before {
        top: 0;
        transform: rotate(135deg);
    }

    &__checkbox:checked + &__button &__icon::after {
        top: 0;
        transform: rotate(-135deg);
    }
}